KR20090005474A - Vehicle stability control device and method - Google Patents

Abstract

An apparatus for controlling posture for vehicles is provided to secure control stability and ride comfort of the vehicles by controlling drive of actuator for controlling rigidity of the stabilizer according to a roll moment determined by comprehensively considering a traveling state of the vehicles. An apparatus for controlling posture for vehicles contains a vehicle speed sensor(11) sensing a velocity of car, a steering angle sensor(12) sensing the steering angle of vehicle, a lateral acceleration sensor(13) sensing horizontal acceleration of the vehicles, an actuator(45) controlling rigidity of a stabilizer bar in which the vehicles is equipped and an ECU(20).

Description

Vehicle attitude control device and its attitude control method {vehicle stability control device and method}

1 is a block diagram illustrating a vehicle attitude control device according to an embodiment of the present invention.

2 is a flowchart illustrating an attitude control method of a vehicle attitude control device according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

11: vehicle speed sensor 12: steering angle sensor

13: lateral acceleration sensor 20: ECU

21: receiver 22: calculator

23: determination unit 24: rigidity control unit

30: Memory 40: Stabilizer Bar

45: actuator

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle attitude control device and a control method thereof, and in particular, by adjusting the driving of the actuator to adjust the stiffness of the stabilizer bar according to the roll moment determined in consideration of the driving state of the vehicle as a whole. And it relates to a vehicle attitude control device and a control method for ensuring a ride comfort.

In general, in the suspension system of a vehicle, a stabilizer bar is mounted to the vehicle body in a transverse direction so that the vehicle itself has a rolling of the vehicle body caused by a change in the relative attitude of the left and right suspensions while driving. By mitigating the roll stiffness that is present, it is possible to further stabilize the behavior of the vehicle body.

This stabilizer bar is applied only when there is a difference in the movement of the wheels, so that the movement of the left and right wheels is equal to the movement of the outer wheels or the inner wheels when the cornering occurs. The inclination is minimized, the roll phenomenon of the vehicle body is suppressed, and the ride comfort and the vehicle body are stabilized.

In controlling the stiffness adjustment of the stabilizer bar, since the vehicle posture control is performed using the conventional steering angle and the vehicle speed, the stiffener bar is released during driving on a flat road to secure a riding comfort and stabilizer during rapid steering. The rigidity of the bar was applied to ensure steering stability.

However, since the vehicle attitude control is performed without considering the behavior of the vehicle under uneven road conditions or unpredictable road conditions, there is a limit to the performance improvement of the vehicle attitude control.

An object of the present invention is to control the driving of the actuator to adjust the rigidity of the stabilizer bar according to the roll moment determined in consideration of the driving state of the vehicle as a whole, as well as to ensure the stability of the vehicle and the riding comfort, It is to improve the performance of the posture control.

Vehicle attitude control apparatus according to an embodiment of the present invention for achieving the above object is a vehicle speed sensor for sensing the speed of the vehicle; A steering angle sensor for detecting a steering angle of the vehicle; A lateral acceleration sensor for sensing lateral acceleration of the vehicle; An actuator for adjusting the rigidity of the stabilizer bar mounted to the vehicle; And calculating a roll measurement value by using the detected vehicle speed, steering angle, and lateral acceleration, and when the difference between the calculated roll measurement value and a preset threshold value exceeds a predetermined value, According to claim 1, characterized in that it comprises an ECU for controlling the actuator.

Preferably, the ECU includes a receiver for receiving the speed, steering angle and lateral acceleration of the vehicle detected from the vehicle speed sensor, the steering angle sensor and the lateral acceleration sensor; A calculator configured to calculate a roll measurement value of the vehicle using the received vehicle speed, steering angle, and lateral acceleration, and calculate a difference between the roll measurement value and a preset threshold value; A determination unit determining whether the difference exceeds a predetermined value; And a stiffness adjustment unit for controlling the stiffness of the stabilizer bar by driving the actuator so that the difference is greater than a predetermined value, and the roll moment corresponding to the excess is reflected in each displacement of the stabilizer bar. It is characterized by.

More preferably, the actuator is characterized in that it comprises any one of an electric motor, a hydraulic modulator.

In addition, the attitude control method of the vehicle attitude control device according to an embodiment of the present invention includes the steps of receiving the speed, steering angle and lateral acceleration of the vehicle detected from the vehicle speed sensor, the steering angle sensor and the lateral acceleration sensor; Calculating a roll measurement value of the vehicle using the received vehicle speed, steering angle, and lateral acceleration information; Calculating a difference between the roll measurement and a preset threshold; Determining whether the difference exceeds a predetermined value; And if the difference exceeds a predetermined value, adjusting the rigidity of the stabilizer bar by driving the actuator according to the roll moment corresponding to the excess value.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a block diagram illustrating a vehicle attitude control apparatus according to an embodiment of the present invention.

Referring to FIG. 1, a vehicle attitude control apparatus according to an exemplary embodiment of the present invention includes a vehicle speed sensor 11, a steering angle sensor 12, and a lateral acceleration sensor. (13) and the difference between the roll measurement calculated using the actuator 45 for adjusting the rigidity of the stabilizer bar 40 installed on the front wheel and the rear wheel, and the vehicle speed, the steering angle and the lateral angular velocity, and the preset threshold value. When the value exceeds a predetermined value is configured to include the ECU 20 for controlling the drive of the actuator 45 according to the molar moment corresponding to the excess.

The vehicle speed sensor 11 is called a wheel speed sensor that can sense the speed of the vehicle, and detects the speed of the vehicle to provide the detected speed signal to the ECU 20.

The steering angle sensor 12 detects a steering angle of the vehicle and provides the detected steering angle signal to the ECU 20. The steering angle sensor 12 is installed on a steering shaft (not shown) of the steering wheel, and detects the steering angle according to the driver's steering wheel manipulation.

The lateral acceleration sensor 13 detects lateral acceleration of the vehicle and provides the detected lateral acceleration signal to the ECU 20.

The stabilizer bar 40 is disposed along the transverse direction in the vehicle body. The stabilizer bar 40 functions as an auxiliary spring for supporting the left and right wheels generated when the vehicle body is rolled, and when the left and right wheels move in phase, they do not receive force, and when they move in reverse phase, they are left and right by torsional elastic force. Constrain the movement of the wheels to reduce the roll behavior of the body.

The ECU 20 detects the driving state of the vehicle from the vehicle speed sensor 11, the steering angle sensor 12, and the lateral acceleration sensor 13 to adjust the rigidity of the stabilizer bar 40 installed at the front and rear wheels. Function to control the operation of 45).

Here, the ECU 20 operates to exert a force on the stabilizer bar 40 connected to the actuator 45 to optimally control the driving state of the vehicle, that is, the attitude and stability of the vehicle.

In addition, the ECU 20 controls the actuator 45 by controlling and outputting a current value in various ways such as PWM (Pulse Width Modulation).

The actuators 45 are respectively installed on stabilizer bars 40 provided on the front and rear wheels, respectively.

The actuator 45 is a device for adjusting the rigidity of the stabilizer bar 40 and may be configured as an electric motor or a hydraulic modulator using a motor and a gear.

When the actuator 45 is configured as a hydraulic modulator, the ECU 20 controls the flow rate flowing into the front and rear actuators 45 by the operation of the actuator 45 and finally controls the rotation angle of the actuator 45. To control the roll angle of the vehicle.

Accordingly, the ECU 20 actively controls the state of movement of the vehicle by controlling the hydraulic flow rate of the hydraulic actuators attached to the front and rear wheels of the vehicle, thereby simultaneously realizing the riding comfort and adjustment stability that cannot be obtained from the stabilizer bar 40. It becomes possible.

In further detail, the ECU 20 applies the speed, steering angle, and lateral acceleration received from the vehicle speed sensor 11, the steering angle sensor 12, and the lateral acceleration sensor 13 according to a preset calculation method, that is, the roll measurement value, that is, Calculate the roll angle value, calculate the difference between the calculated roll angle value and the preset threshold value, and control the driving of the actuator 45 according to the roll moment proportional to the excess when the calculated difference exceeds a certain value. do. At this time, if the difference does not exceed a certain value, that is, there is no roll angle, it is considered that there is no height change.

The ECU 20 includes a receiver 21, a calculator 22, a determiner 23, and a stiffness adjuster 24.

The receiver 21 receives the speed, the steering angle, and the lateral acceleration of the vehicle detected from the vehicle speed sensor 11, the steering angle sensor 12, and the lateral acceleration sensor 13.

')을 계산한다.The calculation unit 22 calculates the roll angle value ('

Calculate ').

'는 차량의 속도이고, '

'은 전륜센터와 후륜센터 사이의 직선거리이고, '

'는 전륜 조향각이며, '

'는 차량 특성 속도이다. 이와 같은 변수를 이용하여 계산된 값은 횡가속도 값('

')이다. 여기에서, '

'는 다음의 수학식 2에 의해 계산된다.From here, '

'Is the speed of the vehicle,'

Is the straight line distance between the front and rear wheel centers,

Is the front wheel steering angle,

'Is the vehicle characteristic speed. The value calculated using these variables is the lateral acceleration value ('

')to be. From here, '

'Is calculated by the following equation (2).

'는 언더 스티어 특성 게인으로, 미리 정의되어 있는 값이다.From here, '

'Is an understeer characteristic gain, which is a predefined value.

Here, 'Mass' is the body mass, 'H_roll' is the height from the roll sensor to the center of gravity, and 'K_roll' is the roll stiffness.

In addition, the calculation unit 22 calculates the difference between the roll angle value and the preset threshold value. In this case, the preset threshold value is a state previously stored in the memory 30.

The determination unit 23 determines whether the difference calculated by the calculation unit 22 exceeds a predetermined value.

If the difference calculated by the calculation unit 22 exceeds a predetermined value, the rigidity adjusting unit 24 generates a roll moment corresponding to the excess amount according to the generated roll moment. The drive of the actuator 45 is controlled. The stiffness of the stabilizer bar 40 is adjusted by driving the actuator 45 so that the roll moment proportional to this excess is reflected in each displacement of the stabilizer bar 40.

The attitude control method of the vehicle attitude control device having such a configuration will be described below with reference to FIG. 2.

The receiver 21 of the ECU 20 receives the speed, the steering angle, and the lateral acceleration of the vehicle detected from the vehicle speed sensor 11, the steering angle sensor 12, and the lateral acceleration sensor 13 (S101).

Next, the calculation unit 22 of the ECU 20 calculates the roll angle value by using the above-described Equation 1 for the speed, the steering angle, and the lateral acceleration of the received vehicle (S103).

Next, the calculator 22 calculates a difference between the calculated roll angle value and a preset threshold value (S105). Here, the preset threshold value is a state previously stored in the memory 30.

Next, the determination unit 23 determines whether the calculated difference exceeds a predetermined value (S107).

As a result of the determination in step S107, when the calculated difference does not exceed a predetermined value, the stiffness adjusting unit 24 of the ECU 20 stops driving the actuator 45 for adjusting the stiffness of the stabilizer bar 40. By adjusting so as not to add rigidity to the stabilizer bar 40 (S108).

As a result of the determination in step S107, when the calculated difference exceeds a predetermined value, the stiffness control unit 24 controls the driving of the actuator 45 according to the roll moment corresponding to the difference to the rigidity of the stabilizer bar 40 To adjust (S109).

In this way, since the control target of the vehicle is determined, it is possible to perform a consistent attitude control regardless of the variation of the vehicle conditions.

In the present exemplary embodiment, the roll angle value is calculated using the speed, the steering angle, and the lateral acceleration of the vehicle, but the present invention is not limited thereto. Control can be performed.

The present invention is not limited to the embodiments described above, and various modifications and changes can be made by those skilled in the art, which are included in the spirit and scope of the present invention as defined in the appended claims.

According to the present invention as described above by driving the actuator to adjust the rigidity of the stabilizer bar according to the roll moment determined in consideration of the driving state of the vehicle as a whole, there is an effect that can secure the adjustment stability and ride comfort of the vehicle.

According to the present invention as described above, if the difference between the roll angle value calculated using the vehicle's speed, steering angle and lateral acceleration exceeds a predetermined threshold value, the roll moment is proportional to the actuator. By applying, not only can the posture control be performed consistently regardless of the change of the vehicle conditions, but also the effect of preventing the vehicle from overturning can be obtained.

Claims (4)

A vehicle speed sensor detecting a speed of the vehicle; A steering angle sensor for detecting a steering angle of the vehicle; A lateral acceleration sensor for sensing lateral acceleration of the vehicle; An actuator for adjusting the rigidity of the stabilizer bar mounted to the vehicle; And The roll measurement value is calculated using the detected vehicle speed, steering angle, and lateral acceleration, and when the difference between the calculated roll measurement value and the preset threshold value exceeds a predetermined value, the roll moment corresponding to the excess value is determined. And a ECU for controlling the actuator. The method according to claim 1, wherein the ECU is A receiver configured to receive the vehicle speed, steering angle, and lateral acceleration detected from the vehicle speed sensor, the steering angle sensor, and the lateral acceleration sensor; A calculator configured to calculate a roll measurement value of the vehicle using the received vehicle speed, steering angle, and lateral acceleration, and calculate a difference between the roll measurement value and a preset threshold value; A determination unit determining whether the difference exceeds a predetermined value; And If the difference exceeds a predetermined value, including a rigidity adjustment unit for adjusting the rigidity of the stabilizer bar by driving the actuator to compensate for the roll moment corresponding to the excess in each displacement amount of the stabilizer bar Vehicle attitude control device characterized in that. The method of claim 1, wherein the actuator Attitude control device for a vehicle comprising any one of an electric motor and a hydraulic modulator. In a posture control method of a vehicle attitude control device including a vehicle speed sensor, a steering angle sensor, a lateral acceleration sensor and an actuator for adjusting the rigidity of the stabilizer bar, Receiving a speed, a steering angle, and a lateral acceleration of the vehicle detected from the vehicle speed sensor, the steering angle sensor, and the lateral acceleration sensor; Calculating a roll measurement value of the vehicle using the received vehicle speed, steering angle, and lateral acceleration information; Calculating a difference between the roll measurement and a preset threshold; Determining whether the difference exceeds a predetermined value; And And controlling the stiffness of the stabilizer bar by driving the actuator according to the roll moment corresponding to the excess when the difference exceeds a predetermined value.

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